Exclusive B → M ν over(ν, ̄) ( M = π, K, ρ, K^* ) decays and leptophobic Z^′ model

We consider the exclusive flavor changing neutral current processes B → M ν over(ν, ̄) ( M = π, K, ρ, K^* ) in the leptophobic Z^′ model, in which the charged leptons do not couple to the extra Z^′ boson. We find that these exclusive modes are very effective to constrain the leptophobic Z^′ model. In the leptophobic Z^′ model, additional right-handed neutrinos are introduced and they can contribute to the missing energy signal in B → M + E/ decays. Through the explicit calculations, we obtain quite stringent bounds on the model parameters, | U_{s b} ^Z′ | {less-than or slanted equal to} 0.29 and | U_{d b}^Z′ | {less-than or slanted equal to} 0.61, from the already existing experimental data. We also briefly discuss an interesting subject of massive right-handed neutrinos, which might be connected with the dark matter problem.